Both my 29645’s have excessive gearbox chatter on high. I’ve replaced the worm shaft bushing and made bushings to take up slop on other spots in the gearbox. Using red n tacky, and been working on Emerson’s a while. I’ve had no problems on several single bearing jr’s And no issues with many other single bearing Emerson’s. But so far 2 29645’s and 2 chattery gearboxes on the left hand sweep. I’m thinking it’s a design flaw or the higher speed is causing something weird to happen. I’ve got a 27645 which has now become my next project to see if there is a similar result. Anyone else with similar issues?

FWIW....this "Emerson chatter" topic has been brought up a number of times. Typically most are looking at the gearbox, and the worm/rod which runs from the blade to the gearbox as the culprit. In some cases it may be the culprit.

What does happen over time with the Emerson rotor cast iron bearing surfaces and hardened steel shaft I noticed and dealt with in the past was excessive wear on the REAR bearing surface of the rotor. I restored an Emerson 1510 and it would intermittently chatter. I would dump fresh oil in when it would chatter and the chatter mellowed out, but eventually returned. I could grab ahold of the front of the rotor with the front cover and blade off and feel no significant play. The fiber washers were correctly spaced.

I took it into a vocational school tool and die and the instructor found excessive wear on the rear bearing surface of the rotor. He had a student machine the rear cast iron bearing surface larger and machined a brass sleeve of correct tolerance and pressed it in place. The fan ran like new when I reassembled it. No more chatter. Good luck.

If it turns out not to be bearings and it is coming from the gearbox, I have a theory.

I’ve had many fans that I’ve restored that the gearboxes were silent and then I cleaned them and added new grease and they became noisy.

This is my theory. They’ve been run so long without grease or insufficient grease, that the gears have seated and developed wear patterns based on that geometry . When you add grease, it changes the tolerances and causes the gears to ride on a little different contact area. I feel that this causes the noise. Most get quiet eventually, I suppose when the gears reseat with the new geometry.

Also since you’ve replaced gearbox bushings, it may have caused a geometry change.

Russ may be right on the rear brass shaft retainer becoming worn and oval shapped.

Does your shaft rod fit within an opening on rear of gear box? If so may not be related the rear brass shaft nut.

I have run ino this a few times. One time was due to much clear on rear of moror housing which extended gear box and put tension on how worm gear engaged large gear. Another time it was having my large gear shimed by washers to low and the worm gear engagment was clicking along the edge of worm gear due to being centered.

Try removing your oscillator arm and see if you hear clicking. I am suggesting this because once had a fan with to many washers under the neck of the motor. This pushed my motor housing upwards creating tension from neck to oscillator which wanted to slow down the gears faster than the worm gear wanted to spin. This may not be the cause but removing set screw to check for tension is an easy first start

In past you could order replacement 1/2" hardened steel shafts and rotors from Emerson. The shafts are pressed into the housing. It has been found in past swapping same motor rotors and shafts remedied the operation noise problem.

The reason I’m thinking it’s gearbox chatter is a few things. With the car docs stethoscope that’s where the sound is coming from. Oil does nothing for the chatter. But neither does a new gearbox and fiber washers floating the gears with little to no play. They aren’t bottoming out either. And it only does it on the left oscillation sweep. Both fans with the exact same issue. I’ve elected the help of another member to upload a video as sometimes hearing it may spark a memory and hopefully it will. Same fan and exact same problem with both and I’ve been through both with new gearboxes and worm shafts changed out. Same result of no change. The rotor is really nice and tight on both fans with no sign of excessive wear. And no chatter when not oscillating. Just weird

Lucas Beshara wrote: The rotor is really nice and tight on both fans with no sign of excessive wear. And no chatter when not oscillating. Just weirdThe rotor on the Emerson 1510 I was restoring was nice and tight and chattered off and on. I would not of had a clue of any excessive play if the tool & die instructor had not miked the rear rotor bearing diameter and recommend a sleeve.

When your fan is on the back swing of oscillation …...the pressure is on. Why the chatter on one back swing and not the other, h ell if I know. I am not saying shaft and rotor bearing tolerance is the issue. I am just saying don't sweep it under the rug. In past I have swapped out same type rotors and shafts to stop chatter.

I've noticed though that some fans just generally have noisy oscillator mechanism period, I have a couple of 1970s viintage oscillating table fans that both of them make a "chattering" noise when they oscillate regardless of which direction the fan is oscillating. I think its just the nature of oscillating fans no make noise of some sort when they work.

I’m not discounting anyone’s suggestions, and appreciate them all. I’m also really hoping someone has had this same issue on this same fan. I really want to say it’s the worm shaft/gear, but the sound is more like gear mesh. Also sounds like it could be a gear/ rotating piece hammering back and forth. But all have fiber washers floating them and all nice and tight

Woohoo. I found the problem. And DIN DING DING!! Russ is the winner! Both the rotors are wore on the backside.
Now for the sign that is the issue so no other happy fanners have to suffer. First is that it wouldn’t do it right away. It needed to heat up (expand) before it became noticeable. And when it did it was very noticeable. But only on the left hand sweep for these little guys. Still gets me but both exact same

Next is the method to test... hang the rotor off the front of the bearing and check for play. There won’t be any play with it fully engaged. This also threw me in other directions. This could also save you some heartache before reassembly or identifying the problem during disassembly. Simply lifting on the blade won’t show any sign of a problem.

I guess I’ll be sleeving some rotors in the near future. I used a jr rotor to test and it had no play hanging it off the front of the bearing, and now no chattering...

Thanks so much for keeping me on that path Russ! I have a quiet 29645 for the first time in a year

When I had the rotor inspected by the tool & die instructor I asked him about the bearings. He looked at me and said .."what bearings?" If you think about it he is right. The 2 internal rotor surfaces in contact and ride on the 1/2" hardened steel shaft are machined cast iron.

The Emerson with rotor riding on shaft wear can be a tricky "fool ya" culprit making funky perplexing motor noise. You can have the blade off and front motor cover and grab the rotor firmly for play and good luck finding any. The culprit appears to be the rear rotor contact surface with excessive wear due to …..the weight of the blade?

Well I’m officially on team Russ for Emerson chatter. Sleeved rotors can save the rotor rather than tossing it.
And BTW our Emmy 1/2” hardened steel shafts are only .485. Shhhhhhhhh! And a perfectly fitting bushing comes in at .486.

I asked the tool and die instructor to mike and machine if necessary a new shaft to press in for the 1510 originally when I left it with him. When I returned to pick up the motor housing/rotor his assessment was the rear rotor surface needed to be sleeved. All I know is it did the trick, no more chatter after hours of test running it.

When you say the shaft is tapered, are you stating from wear, or factory taper?

I asked the tool and die instructor to mike and machine if necessary a new shaft to press in for the 1510 originally when I left it with him. When I returned to pick up the motor housing/rotor his assessment was the rear rotor surface needed to be sleeved. All I know is it did the trick, no more chatter after hours of test running it.

When you say the shaft is tapered, are you stating from wear, or factory taper?Russ,
Try installing the rotor backwards. The rear bearing surface is slightly under the press-fit diameter. And the front bearing surface is slightly under the rear by a few thou.

It is slightly tapered by a few .001-.002. The rear is larger diam. But not by much at all. After pressing the sleeve into the rotor it would only go over the front of the shaft. I had to put it back into the lathe and skim it for it to slide all the way on

This last one was wrot with issues. She had been rode hard and put away dry for many many years. So, the rotor sleeve stopped the rotor hop, the worst of the chatter. There was still slight chatter from the gearbox and I had a few tricks up my sleeve for that. The worm shaft was down a few thou where it rode in the hex bushing. The hex bushing was worse. I had to press a new one on to get the proper clearance at the mating surface. Then turn down the end and make another bushing.

The oscillator link was the worst I’ve seen and got a before pic of that also. It has new bushings also. Now she is chatter free and runs whisper quiet and .35 amps on low. I had to do these bushings separately as each needed run in on high for several hours before the fan would start on its own

Tom,FWIW...this 1510 chattered so bad after I cleaned out her insides it made it as ugly as I found it before restoration. The vocational school tool and die instructor sleeved the back of the rotor and told me that should take care of the problem. I'll be d amned, but he was on target, after I slapped it back together the chatter was.....gone. Fact Jack.

Glad you got the rattle cured! I have a couple of Emersons that were a bit "chatty" but managed to cure them without sleeving in a new bearing.

On one fan, I used non-detergent 30w oil. The other, I put a small bit of heat shrink wrap on the tip of the oscillator rod (where it should fit into the slot in the hub). Seems that the oscillator rod wears out on the tip, or the slot in the hub it engages gets wallowed out... maybe both.